Compounds having an oxetanyl group are known for a polysilane having an oxetanyl group in a side chain (JP-A 2004-26895), a silsesquioxane having an oxetanyl group in a side chain (JP-A 2003-149822) and a polycarbosilane having an epoxy group or a nitrile group in a side chain (J. Inorg. Organomet. Polym., Vol. 5, No. 1, 1995 75-85).
However, a polycarbosilane having an oxetanyl group in a side chain is not known.
In JP-A 2004-26895, a method for introducing an oxetanyl group into a polysilane is disclosed by reacting a polysilane compound having a halogen group with a compound having an oxetane group and a hydroxyl group.
The polycarbosilane shows an excellent heat resistance and decomposition resistance, therefore it is used as a precursor for a ceramic material and a heat resistant resin material (refer to JP-A H07-118007, JP-A H10-069819 and JP-A H09-013278).